Optical fibers are used in a variety of applications ranging from simple light displays to medical instruments and high speed data transmission. Frequently, it is necessary to interconnect one section of optical fiber to another section in a manner which might be likened to the interconnection or splicing of one electrical wire to another. The interconnections, however, of one optical fiber to another are more complex, since precise alignment of the ends of one optical fiber with the end of another optical fiber in the connector must be made in order to retain a high efficiency of light transmission through the connection.
When releasable connection of one end or the terminal end of an optical fiber to an optical fiber tool, which may be in the form of a releasable head or the like, is required, the alignment problem is compounded by the requirement for continued precision connections being maintained, even after many connections and disconnections have been made.
Connectors for connecting a single optical fiber in a cable or other terminator device with a releasable head are available; and alignment problems are relatively minor. A greater degree of complexity, however, exists when two or more fiber optic cables, such as in a duplexed fiber optic cable, must be interconnected to align the optical fibers in each of the cable terminators or in a cable terminator and a releasable working head of some type, since any misalignment of the optical fibers in the two portions being interconnected causes a significant reduction in the efficiency of light transmission through the connector. Essentially, such connections need to be made with nearly zero tolerance; so that misalignment does not take place.
It has been the practice in the past, when two duplex cables are to be interconnected, to split the end of the cable carrying the two optical fibers into two terminal devices. This means that two different connections have to be made between the two different cables, one connector for each of the optical fibers. This results in a bulky assembly and increases the cost of the connectors, because a separate connector must be used for each of the optical fibers in the cable.
Another approach which has been taken in the past is to use alignment pins (male and female) on the mating cables. The tolerances required make this difficult for ease in connecting and disconnecting the cables and terminal devices from one another when this must be done frequently. In a relatively short time, wear causes enough misalignment to occur that the resultant connection is unsuitable. In such situations, the cable connector must be discarded; and new connectors and/or new cables and operating heads or tools must be substituted for the ones where the misalignment wear has taken place.
The United States patent to Murakami U.S. Pat. No. 5,519,799 discloses a connector for fiber optic cables which fits over an hourglass-shaped guide portion used to terminate a flat tape optical fiber cable. The connector aperture has an internal configuration of an hourglass shape, which then aligns the terminating portions of each of the flat cables to be interconnected. This provides a proper alignment between the cables for the optical fiber array carried within the cables. The structure of the Murakami patent, however, is not adapted for interconnecting and aligning two mating cables having a circular cross section, or for aligning mating coaxial cables.
Two other United States patents to Belenkiy U.S. Pat. No. 5,608,830 and Bernardini U.S Pat. No. 4,711,510 illustrate other prior art optical fiber connectors. The Belenkiy patent is directed to a dual connector assembly, which takes two individual cables and spaces them apart and aligns them for connection. This technique is similar to the one described above where the cables are separated and provided with independent terminators and connectors for interconnection. The Bernardini patent is directed to a connector back shell and does not disclose the manner of interconnecting and aligning a pair of optical fibers carried within a single cable.
It is an object of this invention to provide a simple and effective solution for aligning and connecting multiple optical fibers located within a single cable sheath using a single, simple connector for effecting both the connection and alignment of the terminal ends of the cables being connected.